Source: adapted from C. Ducruet (2003) “The Trans-Scalar Development of Transportation Hubs: A Quantitative Comparison of European and East Asian Container Port Cities in the 1990s”.
There is a relationship between the size of a port and the size of the metropolitan area it is located in, particularly for coastal cities having good port sites. Conventionally, because of high inland transport costs, city size and port size tended to converge. Maritime activities were a direct driver of urban growth. With a limited hinterland, port activities were bound to the level of economic activities of a city as a consumption and production center.
Containerization changed this relationship by supporting the setting of much larger port terminals and by expanding hinterland access. This allowed a higher level of possible divergence between the level of port activity and city size. Intermediate hubs are the most notable example of such a process since little traffic is bound to the hinterland. Ports such as Algeciras and Freeport are major transshipment hubs near cities of relatively small size. Port size can thus be completely unrelated to city size. The setting of gateways also contributes to the divergence between port size and city size since they service vast hinterlands. European gateways, such as Antwerp and Rotterdam, are salient examples of medium-sized cities where the port area is larger than the metropolitan area.